Generally, a power converter is used to perform a power conversion between a DC power and a load in accordance with an on or off control of a plurality of semiconductor power switching elements (hereinafter, simply referred to as “switching elements”). It is known that such power converter has multiple operation modes.
Japanese Patent Laying-Open No. 2008-54477 (PTD 1) describes a voltage converting device having a plurality of DC voltages as inputs and outputting a plurality of DC voltages. In the voltage converting device described in PTD 1, operation modes are changed by switching the connection between a terminal of an energy storage device (coil) and a plurality of input potentials as well as a plurality of output potentials. The operation modes include a mode in which two DC power sources are connected in parallel for supplying electric power to the load.
Japanese Patent Laying-Open No. 2010-57288 (PTD 2) describes a structure of a power source device which includes a first power storage unit and a second power storage unit, and is provided with a switch for switching a series connection and a parallel connection between the power storage units. Specifically, the power source device of PTD 2 has an operation mode in which the first power storage unit and the second power storage unit are connected in series and an operation mode in which both are connected in parallel.
Japanese Patent Laying-Open No. 2002-125363 (PTD 3) and Japanese Patent Laying-Open No. 2006-222593 (PTD 4), for example, describe a structure configured to change a gate resistance so as to variably control a change rate of a voltage or a current (typically, a gate voltage), namely a switching speed of a control electrode when it is turned on or turned off as a drive circuit of switching elements which constitute a power converter.